Hydraulic tapping device



-' Dec. 25, 1951 Filed Sept. 4, 1948 c. E. ADAMS HYDRAULIC TAPPINGDEVICE FIG.

2 SHEETS-SHEET 1 JNVENTOR. GEO/L E. ADAMS Dec. 25, 1951 c. E. ADAMSHYDRAULIC TAPPING DEVICE 2' SHEETS-SHEET 2 Filed Sept. 4, 1948 FIG. 2

INVENTORK CEO/L E. ADAMS Patented Dec. 25, 1951 i HYDRAULIC TAPPINGDEVICE Cecil E. Adam s, Columbus, Ohio, assignor to The DenisonEngineering Company, Columbus, Ohio, a corporation of Ohio ApplicationSeptember 4, 1948, Serial No. 47,861

8 Claims.

This invention relates generally to hydraulic.

apparatus and is particularly directed to apparatus for tapping holes inmetal, or, other material.

The invention also relates to hydraulic circuits and more particularlyto a circuit of the type shown in my copending application Serial No.682,974, new Patent No. 2,512,731, issued June 27, 1950, filed July 11,1946, of which this application is a continuation-in-part An object ofthis invention is to provide .a hy-.

draulically actuated tapping machine, which will be automatic in itsoperation and which may be set to successively tap holes in objectsautomatically without undue attention bytheoperator.

An object of the invention also is to provide a hydraulic circuit for atapping machine; the latter having a hydraulically actuated motor and anautomatic control valve mechanism of the type shown in my Patent No.2,561,766, which was.

granted July 24, 1951 on acopending application, Serial No. 600,736,filed June 21, 1945, whereby the hydraulic motor of the tappingv machinemaybe caused to operate in one direction to eiiect the tapping of a holeand automatically reversed.

when the hole has been tapped to the proper depth, the reverse operationof the fluid motor withdrawing the tap for a succeeding tapping. op-

eration.

. A still further object of the invention is to provide a hydraulicsystem. for a tapping machine which system will be automatic inoperationand.

have a control valve mechanism so constructed that in the event undueforce is required to tap the hole the fluid motor which operates the tapwill be reversed to withdraw the tap before breakage of the tap, or,other mechanism, might occur.

A'further object of the invention is to provide the hydraulic systemmentioned in the preceding paragraph with additional control mechanismto effect the automatic operation of an indexing table forming a part ofthe tapping apparatus, the first control mechanism being operative toefiect the actuation of the index table at the conclusion of "a tappingoperation, this table actuation taking place automatically and withoutattention by the operator.

Another object of the invention is to provide a tapping machine having afluid motor and automatic valve mechanism for' controlling the operationthereof, the fluid motor having a lead screw coupled thereto, the leadscrew cooperating with a stationary nut, or, other device, wherebyrotation of the 'fiuid motor will cause similar rotation of the screwandlongitudinal movement thereof, the direction of rotationandlongitudinal move..

ment being dependent upon the direction of rotation of the fluid motor,vthe valve mechanismbeing such that longitudinal movement of the" leadscrew to a predetermined point will effect-the actuation of the valvemechanism to cause a reversal of the fluid motor thus effecting thereverse rotation of the lead screw and longitudinal movement thereof inthe opposite direction.

Further objects and advantages of thepresent invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred form of embodi-- merit of the invention isclearly shown.

In the drawings:

Fig. 1 is a side elevational view, partly inver tical section, of ahydraulic tapping machine formed in accordance with the presentinvention. Fig. 2 is a diagrammatic view of the hydraulic systememployed in the tapping machine shown in Fig. 1, parts of the mechanismforming the circuit being shown in section.

Referring more particularly to the drawings,.

the numeral 28 designates generally the tapping machine. This tappingmachine includes a'press' frame 21 having base, uprightand head sections22 to 24.respectively. The frame is provided in the lower portion at therear with areservoir 25 v forming a part of the hydraulic system, whichis designated generally by the numeral 26. forward portion, the basesection of the frame has an index table supported thereby, the indextable being indicated generally by the numeral 2'5.- The press frame andthe index table are substantially identical with the press frame andindex table set forth in the above mentioned copending applicationSerial No. 682,974.-

The head section 2d of the press frameis pro? vided with a fluid motoroperated tapping mecha--' nism, indicated generally by the numeral 23,and

the control mechanism 35 by which the'operation of the entire apparatusis controlled, a second control mechanism 3i being provided-inconnection with the index table to effect the control of such device.

Attention is directed to the hydraulic circuit shown in Fig. 2. It isbelieved that a completerelief valve 33, these elements being connected;

by a pipe line 34 toform a fluid pressure source;

a return line 35 extends from the relief valve to At its the reservoir25 to conduct fluid to the latter when the pressure of the sourceincreases beyond a predetermined amount. A pipe line 36 extends from therelief valve 33 to the inlet of the main control valve mechanism 30, theinlet being designated by the numeral 3'! and frequently hereinaftertermed the pressure port.

The control valve mechanism has been illustrated and described in detailin both of the above mentioned copending applications and will only bedescribed in a general manner herein sunflcient to afford anunderstanding of the present invention. The control valve mechanismincludes upper and lower motor ports 38 and 40 arranged above and belowthe inlet port 31 and a pair of outlet ports 4| and 42 arranged aboveand below the motor ports 38 and 40. Between the inlet port 31 and thelower motor port 40, the valve mechanism is provided with another port43, which is connected at all times with a bore 44 in which a manualcontrol valve 46 is disposed. Between the lower motor port 43 and thelower exhaust port 42, the valve mechanism is provided with stillanother port 45, which will hereinafte be termed a control port.

The bore 44 receives a hollow spool constituting the control valve 46which is employed to manually efiect the initiation of operation of thehydraulic system. It is also effective to discontinue the operation ofthe system when it is necessary, or, desirable. Valve 43 is biasedtoward a centered position by coil springs 41 and 48 arranged at theupper and lower ends of the valve. The hollow interior of the spoolvalve serves to connect exhaust ports 4| and 42, the latter beingconnected by line 56 with the reservoir 25. The valve mechanism 36 isprovided with a pair of valve elements 5| and 52, the former having aninternal chamber 53 for the slidable reception of the valve element 52.Valve element 5| is isposed for sliding movement in the casing 54 of thevalve mechanism and is pro- .vided with a plurality of rows of ports 55to 6| inclusive, these ports being adapted to register with the ports 46to 45 inclusive, in various positions of longitudinal movement of thevalve element 5|. Valve element 5| is normally disposed in the positionshown in Fig. 2, where it is yieldably held by a coil spring 62, thecoil spring permitting the valve element to be moved either up or downfrom the position shown in Fig. 2. Movement of the valve element 5| isefiected through a shipper rod 63 secured to and depending from thelower end of the valve element.

The valve element 52 comprises a spool-like body having a groove 64 forestablishing communication between certain sets of ports in the valveelement 5|. The spool member 52 is normally maintained in the lowermostposition in the chamber 53 by a coil spring 65, which permits upwardmovement of the element 52 in response to the introduction of fluidpressure into the chamber 53 at the lower end of the element 52. Whenthe spool is moved in an upward direction, it will establishcommunication between a different set of ports than when it occupies thelowermost position shown. The purpose of establishing communicationbetween certain set of ports at different times, will be set forthhereinafter.

With the parts of the mechanism in the position shown in Fig. 2, thevalve element 52 directs fluid pressure from the source into the lowermotor port 40 from which it will flow through line 66 to the fluid motor61 forming a part of the tapping apparatus. The fluid exhausted from themotor, hows through line 68 to the upper motor port 38 from which itwill flow through ports 66 to the interior of the valve element 5| abovethe element 52 and outwardly therefrom through ports 6| to the exhaustport 4|. This fluid then flows through line 50 to the reservoir 25. Whenfluid is flowing to the fluid motor 61 through the line 66 in the mannerjust described, the motor will be operated in a reverse direction,causing the lead screw 10, which is coupled with the motor to alsorevolve in a reverse direction, whereby a nut, or, similar element Hwhich is fixed to the frame 2| will effect the longitudinal movement ofthe lead screw in an upward direction, this movement being transmittedthroughan arm 12 to the shipper rod 63 after the lead screw has moved asufficient distance to cause the outer end of the arm 12 to engage acollar 13 secured to the shipper rod. Arm 12 may be forked to extendaround the shipper rod and be readily removable and it must have aswivel connection with the lead screw to allow rotation of the lat-'-ter. The final stage of upward movement of the lead screw 10 will causethe shipper rod 63 and valve element 5| to be moved upward until ports51 no longer register with the lower port 40. When this registration isinterrupted, fluid flow from the pressure source through line 66 will bediscontinued.

Ports 58 are so arranged in valve element 5| that they will be broughtinto registration with port 43 in the body 54, simultaneously withtheinterruption of communication between ports 51 and 40. The fluidpressure from the source will then be directed through ports 58 to port43. When valve element 46 is in the position shown the fluid pressurefrom the source will be directed from the port 43 to the bore 44 fromwhich it will flow into the port 38 thence through port 60, the chamber53, ports 6| and 4| and be directed to-the reservoir 25 through line 56.At this time, the pump 32 will be unloaded and the tapping machine willbe inoperative, the lead screw being in a retracted position ready forthe next operation. As long as valve spool 46 remains in the positionshown, the tapping mechanism will remain idle. When it is desired toeffect a cycle of operation of the apparatus, the valve spool 46 ismoved downwardly through the rotation of an eccentric pin 14 to aposition wherein the head 15 at the upper end of the valve spool 46 willinterrupt communication between bore 44 and port 38. The fluid from thepressure source will then be directed through line 16 to the secondarycontrol valve mechanism 3|, which mechanism governs the operation of theindex table. Attention is directed to the copending application SerialNo. 682,974 for a detailed description of the operation of mechanism 3|and the index table, it being suflicient here to state that when fluidis introduced through line 16, the mechanism 3| will operate to causethe index table disc I1 to move, or, index a set member of degrees afterwhich fluid flowing through line 16 will be directed through line 18back to the control port 45 of the mechanism 30. This fluid will flowthrough ports 55 in element 5| to the chamber 53 at the lower end ofvalve element 52, the fluid pressure causing the element 52 to moveupwardly in opposition to the force of spring 65 to a position whereinthe groove 64 will establish communication between ports 59 and ports60. Ports 59 are disposed at all times in communication with the inletport 3'! and when connected by the groove 64 with ports .60, will directfluid pressure from the source through ports 60 to the upper motor port48 and line 68 to the motor 61. This fluid will cause the motor 61 torotate in adirection which will in turn cause the lead screw to coactwith the .nut .11 and move in a downward direction, this direction ofmovement of the lead screwand the direction of rotation of the motor 61necessary to cause the same being hereinafter termed the forwarddirection.

When fluid is introduced to. motor t1 through line 63, fluid will be.exhausted from the motor 6'! through line 66. This fluid will flowthrough ports 40 and 51 to transverse ports 19. formed in the lowerportion of the spool 52, these ports then being in registration withports 51. Fluid entering through the ports 51 will flow upwardly througha central bore 823 and outwardly through a bore 8| in the top of valveelement to the exhaust port M. Bore B8 is of such size that it willoffer resistance to fluid flow therethrough causing an increase inpressure on the fluid in ports 19. This pressure will be transmitteddownwardly through bore 82 to the chamber 53 atthe lower end of thevalve spool 52. This pressure will serve to retain the valve spool 52,in the elevated position after fluid flow to line 16 is interrupted; itwill be noted at this time that when the lead screw is retracted andvalve element 5| is moved in an upward direction, ports 51 will be movedout of registration with port 453 and ports 58 will bemoved intoregistration with ports 43. Upon initial downward movement of the leadscrew 1i! at the beginning of a cycle of the motor 61, a coil spring 62will move the valve element St downwardly again,inte'rruptingcornmunication between the ports 53 and 43 and reestablishingcommunication between ports 51 and 40. Initial operation of the motor6'! is possible due to the provision of a set of ports til-A in valveelement 5|, which ports 51-A. register with the lower motor port 40,while ports 58 are registering with ports 43. The exhaust fluid duringthe initial operation of motor 61 may flow through line 66 to port 40and through ports 51- A to ports 18, then after initial downwardmovement of the lead screw and corresponding movement of valve element5|, communication will be established between ports 45) and 1a throughthe ports 51.

Forward rotation of motor 61- and downward movement of the lead screw1ll will continue until fluid flow to the motor is interrupted, or,exhaust flow from the motor is discontinued. Either of these conditionswill cause an interruption to the downward movement of the lead screw.It will be noted that relief valve 33 may be so set that in the eventthe resistance to movement on the part of the lead screw becomessufliciently great, the relief valve will by-pass fluid from the pump 32directly to the reservoir 25 and fluid pressure will cease to flow tothe motor 61. When this fluid flow ceases, motor 61 will stop,discontinuing the flow of exhaust fluid through line 66. When this flowstops the fluid pressure in ports 19 and in the chamber below valve 52will be dissipated permitting spring 65 to move valve 52 to its loweredposition wherein the groove 64 will establish communication between theinlet port 31 and the lower motor port 40. Fluid pressure from thesource may then flow directly to the motor 61 to cause reverse movementthereof effecting an upward movement of lead screw 10 and exhaust offluid through line 68, ports 38, 60, and GI, to the exhaust port 4!.When the lead screw has completed' its retractive movement, valveelement 5| will be moved to a position to interrupt fluid flow-betweenports 51 and 40, at which time r0- tationoi motor 61 will bediscontinued. If .valve element occupies position shown in Fig. 2, themechanism will come to rest; if, however, valve dd-has been locked inits lowered position fluid flowfrom the pressure source will be directedto the index table to cause it to perform an index-ing operation afterwhich another cycle ofoperation "of motor 61 will be initiated. In theevent, the fluid motor 61- is not stoppe in the manner set forth above,the arm 12 will engage a lower collar 84 fixed to the shipper rod 63 andmove the shipper rod in a downward direction, also moving valve element5! downward until'a groove 85 atthe upper end of the valve elementimmediately under the head 86 thereof, establishes communication betweenup per motor port '38 and exhaust port 4!. When this communication isestablished fluid pressure will'b'e directed to exhaust, rather, thanthrough line 58 and fluid motor 61 will stop. The'flow of the exhaustfluid'will then be discontinued. Reverse rotation of the motor 61 willthen be started in the same manner described above. It will thus be seenthat a hydraulic systemhas been provided which will permit holes to betapped to a predetermined depth, or, permit the tapping operation to bereversed and the tap withdrawn if a predetermined resistance to thetapping operation is encountered. The mechanism for performing thetapping operation may be varied in numerous ways, the mechanism shownbeingselected for illustration only. In this mechanism, the drive shaft81 of the fluid motor 61 has a connection with the lead screw whichpermits the latter to move longitudinally due to its reaction with thenut 1!, without interrupting the driving connection. It will be obviousthat the lead screw and the nut 1| should be made readily removable sothat lead screws provided with diflerent threads may be readilysubstituted therefor. The lower end of the lead screw is equipped with asuitable collet 88 to receive the tap essential in tapping operations.

I1.claim:

i. A hydraulicaily operated tapping machine comprising areversible fluidmotor; a source of fluid pressure; control valve mechanism between fluidpressure source and said fluid motor, said mechanism having a valvemember operative in a first position to cause rotation of said motor ina first direction and in a second position to cause rotation of saidfluid motor in the opposite direction, said valve member beingresponsive to fluid pressure to move to said first position; fluidpassage and orifice means for utilizing exhaust fluid from said fluidmotor during operation in said flrst direction to maintain said valvemember in said first position; a lead screw coupled for rotation withsaid fluid motor; a stationary nut cooperating with said lead screw tocause longitudinal movement thereof during rotation of said fluid motor;and motion transmitting means between said lead screw and said controlvalve mechanism, said motion transmitting means being operative tointerrupt the flow of fluid pressure from said source to said fluidmotor to discontinue opera tion thereof in said first direction whensaid lead 7 screw reaches a predetermined position in its longitudinalmovement.

2. A hydraulically operated tapping machine comprising a source of fluidpressure; a reversible fluid motor; a control valve mechanism betweensaid pressure source and said motor; tap-carrying means supported forlongitudinal and rotary movement, and coupled to said fluid motor,rotation of said motor causing longitudinal and rotary movement of saidtap-carrying means; a valve element in said control valve mechanismresponsive to fluid pressure to move to a position to cause the rotationof said fluid motor in a certain direction; a second valve element insaid control valve mechanism operative in one position to interrupt therotation of said fluid motor in said certain direction; and motiontransmitting means between said tap-carrying means and said second valveelement, said motion transmitting means serving to move said secondvalve element to said one position when said tapcarrying means reaches apredetermined position during longitudinal movement thereof.

3. A hydraulically operated tapping machine comprising a source of fluidpressure; a reversible fluid motor; a control valve mechanism betweensaid pressure source and said motor; tap-carrying means supported forlongitudinal and rotary movement, and coupled to said fluid motor,rotation of said motor causing longitudinal and rotary movement of saidtap-carrying means; a valve element in said control valve mechanismresponsive to fluid pressure to continue the rotation of said fluidmotor after such rotation is initiated; the application of fluidpressure to said valve element ceasing upon the interruption of rotationof said fluid motor; and means for moving said valve element to aposition to cause rotation of said fluid motor in the direction toreverse the movement of said tap-carrying means when the application offluid pressure to said valve element ceases.

4. Hydraulically operated tapping apparatus comprising a source of fluidpressure including an adjustable relief valve; a reversible fluid motor;control valve mechanism between said pressure source and said motor,said mechanism having a valve element responsive to the application offluidpressure depending upon the operation of said motor to continuemotor operation in a predetermined direction; means for moving saidvalve element to a position to cause operation of said motor in theopposite direction when the application of fluid pressure to said valveelement is interrupted; tapping means actuated by said. fluid motor,predetermined resistance to operation of said tapping means causing the;

operation of said relief valve to interrupt the flow of fluid pressureto said fluid motor and discontinue the operation thereof, the cessationof motor operation interrupting the application of fluid pressure tosaid valve element.

5. A hydraulically operated tapping machine comprising a source of fluidpressure; a reversible fluid motor; a lead screw coupled to said fluidmotor for rotation therewith; a stationary member cooperating with saidlead screw to cause longitudinal movement thereof upon rotation of saidmotor; an index table having a fluid motor; control valve mechanismbetween said fluid pressure source and said fluid motors, said mechanismhaving valve elements responsive in part to valve 'mechanism beingoperative to actuate the confluid pressure to initiate the operation ofthe first-mentioned fluid motor; motion transmitting means between saidlead screw and said control mechanism, said motion-transmitting trolvalve mechanism at a predetermined stage of movement of the lead screwto direct fluid pressure from said source to said second-mentioned fluidmotor to cause the operation ofv said I index table, and means operatedby said secondmentioned fluid motor substantially at the conclusion ofan indexing operation of the index table to apply fluid pressure to thevalve elements of said control valve mechanism to initiate a cycle ofoperation of said first-mentioned fluid motor.

6. Hydraulically operated tapping apparatus comprising a source of fluidpressure including an adjustable relief valve; a reversible fluid motor;control valve mechanism between said pressure source and said motor;reversing valve means in said mechanism operative when said relief valveby-passes fluid from said pressure source to reverse the direction ofoperation of said fluid motor; and tapping means actuated by said fluidmotor, predetermined resistance to operation of said tapping meanscausing the operation of said relief valve.

7. Hydraulically operated tapping apparatus comprising a source of fluidpressure; a reversible fluid motor; valve mechanism between said pres--sure source and said motor; a reversing valve in said mechanism servingin one position to cause said fluid motor to operate in one direction;means operative when said fluid pressure source reaches a predeterminedpressure to move said reversing valve to another position to cause saidfluid motor to operate in a reverse direction; and tapping meansactuated by said fluid motor, resistance to operation of said tappingmeans causing the pressure of said source to increase.

8. Hydraulically operated tapping apparatus comprising a source offl-uid pressure; a reversible fluid motor; control valve mechanismbetween said pressure source and said motor; a reversing valve in saidmechanism, said valve serving in a first position to cause said fluidmotor to operate in one direction; means in said control valve mechanismoperative when said fluid pressure source reaches a predeterminedpressure to move said reversing valve to a second position to cause saidfluid motor to operate in a reverse direction; tapping means actuated bysaid fluid motor, re sistance to operation of said tapping means causingthe pressure of said source to increase; and means actuated by saidfluid motor after the same has operated a predetermined extent in saidone direction to cause said reversing valve to move to said secondposition in the event the pressure of said source of fluid pressure doesnot increase to said predetermined pressure.

CECIL E. ADAMS.

REFERENCES CITED The following references are of record in the flle ofthis patent:

UNITED STATES PATENTS

